Defects and magnetic structure of CuMnSb

Total energy calculations show that the antiferromagnetic (111) order is not the ground state for the ideal CuMnSb in contrast to the results of neutron diffraction experiments. The magnetic phases of the CuMnSb Heusler alloy were investigated with the aim to clarify the role of defects which exist in real samples (Mn-antisites on Cu, Mn-interstitials, and Cu-Mn swaps). The full-potential supercell approach and the Heisenberg model were used to find the magnetic structure of the CuMnSb with defects. Results of both types of calculations indicate that already low defect concentrations can promote the (111) antiferromagnetic structure. (paper)